Static-operation separators separate bulk materials into two fractions having dissimilar distributions of particle sizes. Separating the fractions is performed in a separation space in which the separation stock, falling in from a separation-stock inlet in the direction of a coarse-stock outlet, is perfused in the transverse direction by a separation gas. Comparatively small particles are entrained by the separation-gas flow and transported to a fine-stock outlet, while comparatively large particles are discharged by way of the coarse-stock outlet.
The ventilation bases of a static separator are aligned so as to be more or less transverse to the movement direction of the separation stock, a step-type arrangement of the ventilation bases often being provided (DE 43 37 215 A1). According to one preferred embodiment, a ventilation base which is configured so as to be substantially planar is provided with a multiplicity of ventilation slots. The ventilation base here may be assembled from a multiplicity of individually replaceable slotted plates. The separation stock falling into the separation space impacts the ventilation base(s) and is perfused there by the separation gas. The dwelling time of the separation stock in the separation space may be increased by the separation stock impacting the ventilation base(s), on the one hand. On the other hand, the separation stock impacting on the ventilation bases causes separation-stock agglomerates, so-called slugs, which are often present to disagglomerate. Both lead to the separation effect of a static separator being enhanced.
Static separators are often combined with dynamic separators, the static separators, as coarse separator, typically being upstream of the dynamic separator which serves as a fine separator. Dynamic separators operate on the basis of separating two fractions of the separation stock which are dissimilar in terms of the distribution of the particle sizes by means of a rotatingly driven separation cage.
A combination of a static separator as a coarse separator, and of a dynamic separator as fine separator in a recirculating grinding mill for cement clinker is known from DE 43 37 215 A1, for example. The static separator therein is downstream of a roller press and is impinged by the latter with separation stock which is comparatively coarse and has a multiplicity of slugs. The coarse stock which has been separated in the static separator is fed back to the roller press, while the fine stock by means of the separation gas flow is infed to a tubular ball mill in which said fine stock is further comminuted. From the tubular ball mill, the separation stock is then infed to the dynamic separator in which a separation of the separation stock into medium-fine stock and finest stock is performed. The finest stock as finished stock is then eliminated from the separation gas in a sorter, while the medium-fine stock is fed back to the tubular ball mill. In the case of the recirculating grinding mill according to DE 43 37 215 A1, the static separator and the dynamic separator are kept apart in terms of both space and function by the interdisposed tubular ball mill. The static separator thus serves substantially for avoiding excessively large particles or slugs being infed to the tubular ball mill.
A device for separating bulk material, in which a static separator and a dynamic separator are disposed in direct succession and integrated in a common housing, thus being perfused by the same separation-gas flow, is known from DE 10 2011 055 762 A1. The upstream disposal of the static separator serves substantially for avoiding impingement of the rotatingly driven and comparatively delicate separation cage of the dynamic separator by large particles and slugs.
It is also disclosed in DE 10 2011 055 761 A1 that, in addition to a main separation-gas inlet for a static separator, additional openings which by means of flaps or slides may be embodied so as to be closable may be provided, on account of which regulation of the separation gas which is infed to the static separator is to be enabled.
Finally, a dynamic separator in the housing of which a bypass duct which bypasses the separation space is integrated is known from DE 42 56 970 C3, by way of which bypass duct part of the dust-air mixture which is infed by way of an inlet may be directed so as to avoid separation in the separation space. On account thereof, targeted influencing of the particle sizes in the finished stock leaving the dynamic separator is to be possible.